Door opening alarm



Dec. 19, 1961 s. PHILLIPS DOOR OPENING ALARM Filed April 19, 1960 21 23 FIG/ FIG-6.

INVENTOR. STROTHER L. PHILLIPS ATTORNEY 3,013,523 DUOR OPENING ALARM Strother L. Phillips, 35 W. Mountain St., Pasadena, Calif. Filed Apr. 19, 1960, Ser. No. 23,164 1 Claim. (Cl. 116-86) The present invention relates generally to audible signalling devices and more particularly to an automatic door opening alarm.

While other more sophisticated electric door alarms are widely available, such alarms may be costly and can be installed only with difficulty and expense after the store, office, or home has been built.

The principal object of my invention, therefore, is to provide an inexpensive audible signalling device that can easily be installed in conjunction with a pivoted, swingable door and its supporting frame.

Another object of my invention is to provide an audible signalling device or automatic door opening alarm that will produce a pleasing alarm or signal.

A further object of my invention is to provide an automatic door opening alarm that will normally only signal or sound when the door is opened.

Other and further objects and advantages of my invention will become apparent in the following description and drawings wherein:

FIGURE 1 is a perspective view partly broken away upper portion of the door and door frame with my invention mounted thereon; 7

FIG. 2 is an enlarged side elevational view of my invention shown in its mounted position disclosing a partial section of the door and door frame, a central section of the resiliently mounted support means, and a partial section of the striker bar, the sectioning being taken on a vertical plane perpendicular to the closed door and door frame and passing through the center of the alarm device as so mounted;

FIGS. 3 and 4 are similar to FIG. 2 showing the modes of operation of my invention;

FIG. 5 is an enlarged partial sectional plan view taken on the plane indicated by the line 5-5 in FIG. 2;

FIG. 6 is a plan view of certain elements of my invention; and

FIG. 7 illustrates a modified use of my invention.

With reference to FIGS. 1 and 2, my automatic door opening alarm 10 is shown installed on a hinged, swingable door 12 and the upper lintel or header 14 of the door framing 16. The alarm 10 comprises the bell assembly support or bracket 18 supporting the bells 29 and the striker mechanism 22.

The bracket 18 may be a flat 'U-shaped supporting member having a relatively long backing strip 19 and a pair of horizontally extending terminal arms 21 at each end of the backing strip. The backing strip 19 is provided with a plurality of screw holes 23 for fastening the bracket to the door frame header 14 with the screws 24-. The outer ends of the terminalarms 21 are provided with small holes 25 for securing the outer hooked ends of the springs 26 thereto.

The bell assembly comprises a central bell supporting member 27 which is suspended between the two springs 26 and secured thereto as shown in FIG. 5. The bells 2i? depend vertically from the ends of the member 27. In the illustrated method of attachment, the upwardly extending bell shanks 28 are provided with cross-drilled hol s 29. The ends of the bell supporting member 27, here shown as a section of tubing, are provided with horizontal crossdrilled holes 30 and a longitudinal slot 31 in the lower portion. As shown in FIGS. 2 and 5, the bell shank 28 is inserted upwardly through the slot 31 and is held in place by the cotter pin 32 which extends through the holes in the tubing and bell shank. The

nited States Patent 0 3,013,523 Patented Dec. 1 9, 1961 inner hooked ends of the springs are secured to the tubing by hooking their hooked ends over the cotter pins 32. The lengths of the springs and bell supporting member are chosen so that when installed between the arms of the door-frame bracket 18, the system will be under tension and the bell supporting member will be substantially centrally disposed with relation to the bracket.

The striker mechanism 22 which is secured to the upper part of the swingable door comprises a striker support 33, an upwardly extending striker bar 34 and a dual action striker cam 35.

The striker support 33 is a T-shaped structure having a base portion 36 and a horizontally extending stem portion 37. The base portion 36 is provided with a plurality of holes 38, see FIG. 6, so that it may be secured to the upper surface of the opening door by the screws 39. The horizontally extending stern portion 37 is provided with a vertical hole 40 which is shaped to conform to the shape of the upwardly extending striker bar 34. A set or thumb screw 41 is threadedly inserted in the end of the stem portion which set screw protrudes into the hole 40 for anchoring the striker bar and preventing its vertical movement after proper adjustment.

The striker bar 34 is slotted and drilled at its upper end with a slot 42 and cross-holes 43 for the reception and pivoting of striker cam 35. A pivoting pin 44 is inserted through the holes 43 and a hole 45 provided in the pivoting portion 46 of the striker cam 35.

Asindicated in FIG. 3, the striker cam 35 has a pivoting portion 46, a relatively long downwardly extending offset portion 47 and a relatively short upwardly ex: tending dual action cam portion 48. As previously described, the pivoting portion 46 is pivotally secured in the slot in the upper end of the striker bar 34. The downwardly extending portion 47 is offset so that its pivot side rests against the door side of the striker bar 34. Thus the striker cam 35 has freedom of motion in one direction but is restricted from moving in the other di rection as will be more fully explained hereinafter. The upwardly extending dual action cam portion 48 is provided with a steep angled forward surface 49 and a more obtuse rear or door-ward angled surface 50.

As shown in FIGS. 1 and 2, the bracket 18 with its bell assembly is secured horizontally on the header 14 of the door frame and is located, preferably, toward the opening side of the door 12. The striker mechanism 22 is then secured to the upper surface of the door 12 so that the cam portion 48 may strike or touch the bell supporting member 27. It will be noted here that the relation between the lengths of the bracket arms 21 and the stem portion 37 is such that the striker bar 34 and its associated cam will be disposed inwardly toward the door from the bell supporting member 27. Also, the striker mechanism is so located on the opening side of the door that the striker cam will contact the member 27 in its central portion.

Now with reference to FIGS. 3 and 4, as the door is opened outwardly, cam face 49 comes in contact with the under portion of member 27. Since the lower portion 47 of the striker cam is abutting the inner surface of the striker bar, the cam is held rigid and the bell supporting member 27 is abruptly lifted, thus ringing the bells 20 and sounding the alarm. The door with the striker mechanism then swings outwardly open in the normal man- In the modification shown in 'FIG. 7, my automatic 4 i i Q door opening alarm is shown as adapted for use between a main inner door 51 and an outer door 52, such as E1 screen door. The bell assembly supporting bracket 18 is mounted on the underside of the door frame header with the shortened terminal arms 21 extending vertically downward. The bell assembly is secured between the two arms as previously described. The striking mechanism is mounted on the inner side of the outer door 52. The length of the stem portion 37 of the striker support 33 is chosen so that the striker bar 34 is disposed inwardly toward the inner door 51 of the bell supporting member 27. The striker bar and dual action cam are reversed in position with relation to the striker support 33 but are in the same relative position to the bell supporting member 27 as shown previously. Thus, as the screen door is opened outwardly in the direction of the arrow 53, the cam action with relation to the bell assembly is as hereinbefore described. It should be noted here, perhaps, that after installation of the bell assembly supporting bracket to the upper part of the door frame and the striker mechanism to the upper part of the door, set screw 41 is loosened and the striker bar 34 adjusted in height until striker cam 35 just touches the lower portion of member 27 sufficiently so as to sound the alarm when the door is opened but to not sound the alarm when the door is closed.

While my invention has been illustrated with certain preferred details of construction, it should be apparent that many modifications may suggest themselves to those skilled in the art. The fastening means used to secure the bell assembly together could be considerably moditied as well as the securing of the bell assembly to the arms of the bracket. Means could be provided in conjunction with one or both bracket arms 21 to vary the tension of the bell supporting springs 26. The striker bar 34, while shown of solid square cross-section could be of square or round tubing or solid round. In the latter case, a longitudinal fiat or groove could be provided to cooperate with the set screw 41 in preventing the striker bar 34 from twisting or turning, thus insuring the proper presentation of the dual action cam to the bell supporting member. While shown as round tubing, the bell supporting member 27 could be of other shapes of tubing or solid materials having any desired or convenient cross-section.

Having thus described and shown a preferred embodiment of my automatic door opening alarm, I do not intend to be limited thereby but only intend to be limited by the spirit of the invention and the scope of the appended claim wherein I claim:

In combination with a door frame having a lintel and a swingable door hingedly mounted therein, a door opening alarm comprising: a bell assembly supported by said lintel above the upper horizontal edge of said door, said bell assembly consisting of an horizontal flat U-shaped bracket secured to said lintel, said bracket having horizontally extending arms perpendicularly disposed to the face of said lintel, a bell supporting member resiliently supported centrally of said bracket between said arms and a plurality of bells depending from said bell supporting member; and adjustable striker means mounted on said door in proximity to said bells to sound an alarm only when said door is opened, said striker means being positioned inwardly of said bell supporting member, said adjustable striker means being adjustable in a vertical direction and including a pivoted cam means movable only in one direction, said cam means being provided with inclined surfaces contacting said bell supporting member in both opening and closing directions.

References Cited in the file of this patent UNITED STATES PATENTS 480,001 Weller m. Aug. 2, 1892 2,735,397 Bishop Feb. 21, 1956 2,912,956 Biernacki Nov. 17, 1959 

